In the Petroleum industry, many process vessels made of metallic material are exposed to high temperature and high pressure internal environments. In such process vessels, it is conventional to line the interior of the metal shell thereof with suitable refractory material which serves to insulate the metal shell from the high temperature of the process, as well as protect the metal from the corrosive and erosive effects of the material being processed within the vessel. It has been conventional heretofore to apply one or more separate layers of ceramic insulation to such vessel interior surface, using metallic anchor members which are typically butt welded to the surface interior. When it has been desired to employ a dual layer of insulation as in applicants' present arrangement, it has also been conventional to use metallic anchors of a first predetermined height for securing the outermost insulation layer to the vessel wall and employ a second set of metallic anchors of greater height or stand-off from the wall for the anchoring of an innermost layer of refractory insulation. Alternatively, as in U.S. Pat. No. 2,525,821, a dual-layer of refractory insulation was applied by inserting steel anchors into the primary layer before it set, to which the secondary layer was attached.
However, these conventional prior art methods of securing a dual layer insulation to the vessel wall have been unsatisfactory in certain hostile corrosive environments within the process vessel and such metallic anchors, particularly those securing the hot face layer of refractory insulation, have been subject to weakening due to the high temperature environment of the process. When such metallic refractory anchors have failed in the past due to corrosion or loss of strength at elevated temperatures, disbonding or spalling of the higher density castable refractory inner lining has occurred permitting separation thereof from the underlying lower density insulation refractory leading to lining failure and premature shutdown of the unit for repair.